In mobile robotics, localization data is understood as the data that determines the position and orientation of an object relative to a reference frame. Accurate localization data is required for proper navigation, path planning, mapping and other tasks in this field. In general, sensing techniques associated with localization can be classified into absolute and relative referencing techniques. Relative techniques include using rotary encoders to keep track of the rotation of the components of the driving trains and wheels of a vehicle. These techniques lack an absolute reference frame and thus usually experience issues with cumulative error and drifting signals.
Some examples of absolute referencing techniques include Global Positioning Systems (GPS) and Inertial Measurement Units (IMUs). GPS works well for global positioning but small scale applications often times require higher resolution/accuracy and GPS cannot provide orientation data, only positioning. On the other hand, IMUs are excellent performers in terms of orientation data but do not perform well for positioning. Lastly, it is relevant to highlight that IMU's performance is significantly compromised when the orientation angle that requires measuring is around an axis which is parallel to the direction of the gravitational field around the device.
The present invention addresses these and other problems.